After the 1929 Arab riots against the Jews, the British commissiones Sir John Hope Simpson to look into the underlying causes of the disturbances. He finds that Jewish land purchase/Arab land sales, Jewish immigration, and the failure to establish self-governing institutions contribute to the unrest. Hope-Simpson is heavily influenced by the anti-Zionist attitudes of other British officials. The Passfield White Paper, issued the same day, uses Hope-Simpson’s findings to suggest restrictions on Jewish land purchase and immigration restrictions. These are implemented ten years later with the May 1939 White Paper.